Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-26T20:53:05.921Z Has data issue: false hasContentIssue false
  • English
  • Français

Simple representation of physiological regulations in a model of lactating female: application to the dairy goat

Published online by Cambridge University Press:  01 February 2008

L. Puillet ,
O. Martin ,
M. Tichit  and
D. Sauvant
L. Puillet*
Affiliation:
UMR INRA-AgroParisTech PNA, 16 rue C. Bernard, 75231 Paris Cedex 5, France UMR INRA-AgroParisTech SAD-APT, 16 rue C. Bernard, 75231 Paris Cedex 5, France
O. Martin
Affiliation:
UMR INRA-AgroParisTech PNA, 16 rue C. Bernard, 75231 Paris Cedex 5, France
M. Tichit
Affiliation:
UMR INRA-AgroParisTech SAD-APT, 16 rue C. Bernard, 75231 Paris Cedex 5, France
D. Sauvant
Affiliation:
UMR INRA-AgroParisTech PNA, 16 rue C. Bernard, 75231 Paris Cedex 5, France
*
E-mail: Laurence.Puillet@agroparistech.fr
Get access

Abstract

A dynamic model of the lactating dairy goat, combining a minimum of mechanistic representations of homeorhetic regulations and a long-term approach, was developed. It describes (i) the main changes in body weight, dry-matter intake, milk production and composition of a dairy goat; (ii) the succession of pregnancy and lactation throughout the productive life; and (iii) the major changes in dynamics induced by the female profile (production potential and body weight at maturity). The model adopts a ‘pull’ approach including a systematic expression of the production potential and not representing any feed limitation. It involves three sub-systems. The reproductive events sub-system drives the dynamics through time with three major events: service, kidding and drying off. It also accounts for the effect of production potential (kg of milk at the peak of lactation) and lactation number (potential reached at the fourth lactation). The regulating sub-system represents the homeorhetic mechanisms during pregnancy and lactation with two sets of theoretical hormones, one representing gestation and the other lactation. The operating sub-system describes the main physiological flows and the energetic requirements linked to these functions through a compartmental structure. Simulations were run in order to test (i) the behaviour of the model at the scale of the productive life for an average profile of female (60 kg at maturity and 4 kg of milk at peak); (ii) the sensitivity of the simulated dynamics (mainly milk production and body reserves) to the production potential and body weight at maturity; (iii) external validation with comparison of model outputs to data from the experimental flock of Grignon and data from the French milk record organization (French organism in charge of animal recording for dairy farmers). The results at the scale of one productive life show the model simulates a relevant set of dynamics. The sensitivity analysis suggests that the model fairly well simulates the link between a female’s ability to produce and mobilise reserves. Finally, external validation confirms the model’s ability to simulate a relevant set of physiological dynamics while pointing out some limits of the model (simulation of milk fat and protein content dynamics, for example). The results illustrate the relevance of the model in simulating biological dynamics and confirm the possibility of including minimum representations of homeorhetic regulations with a simple structure. This simplicity gives an opportunity to integrate this basic element in a herd simulator and test interactions between females’ regulations and management rules.

Keywords

dairy goatsdynamic modelshomeorhetic controlphysiological functions
Type
Full Paper
Information
animal , Volume 2 , Issue 2 , February 2008 , pp. 235 - 246
Copyright
Copyright © The Animal Consortium 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baldwin, RL, France, J, Gill, M 1987. Metabolism of the lactating cow. I. Animal elements of a mechanistic model. Journal of Dairy Research 54, 77–105.CrossRefGoogle ScholarPubMed
Bauman, DE, Currie, WB 1980. Partitioning of nutrients during pregnancy and lactation: a review of mechanisms involving homeostasis and homeorrhesis. Journal of Dairy Science 63, 1514–1529.CrossRefGoogle Scholar
Blackburn, HD, Cartwright, TC 1987. Description and validation of the Texas A and M sheep simulation model. Journal of Animal Science 65, 373–386.CrossRefGoogle Scholar
Bouloc N 1991. Analyse de la forme de la courbe de lactation: application à l’étude des modalités d’allègement du contrôle laitier et de prévision précoce de la production dans l’espèce caprine. PhD thesis, INA Paris Grignon, France.Google Scholar
Chilliard, Y, Rémond, B, Agabriel, J, Robelin, J, Vérité, R 1987. Variations du contenu digestif et des réserves corporelles au cours du cycle gestation–lactation. Bulletin Technique du CRVZ de Theix, INRA 70, 117–131.Google Scholar
Danfaer A 1990. A dynamic model of nutrient digestion and metabolism in lactating dairy cows. PhD thesis, National Institute of Animal Science, Foulum, Denmark.Google Scholar
Faverdin, P, Delagarde, R, Delaby, L, Meschy, F 2007. Alimentation des vaches laitières. In Alimentation des bovins, ovins et caprins (ed. INRA), pp. 23–55. Editions Quae-INRA, Versailles, France.Google Scholar
Forrester, JW 1971. World dynamics. MIT Press Cambridge, Portland, Oregon.Google Scholar
Friggens, NC 2003. Body lipid reserves and the reproductive cycle: towards a better understanding. Livestock Production Science 83, 219–236.CrossRefGoogle Scholar
Friggens, NC, Newbold, JR 2007. Towards a biological basis for predicting nutrient partitioning: the dairy cow as an example. Animal 1, 87–97.CrossRefGoogle ScholarPubMed
Gipson, TA, Grossman, M 1990. Lactation curves in dairy goats: a review. Small Ruminant Research 3, 383–396.CrossRefGoogle Scholar
Martin, O, Sauvant, D 2007. A dynamic model of dairy cow metabolism. Animal 1, 1143–1166.CrossRefGoogle ScholarPubMed
Montaldo, H, Almanza, A, Juarez, A 1997. Genetic group, age and season effect on lactation curve shape in goats. Small Ruminant Research 24, 195–202.CrossRefGoogle Scholar
Morand-Fehr, P, Sauvant, D 1988. Alimentation des caprins. In Alimentation des bovins, ovins et caprins (ed. R Jarrige), pp. 281–304. Institut National de la Recherche Agronomique, Paris, France.Google Scholar
Sauvant, D 1992. Systemic modelling in nutrition. Reproduction, Nutrition, Development 32, 217–230.CrossRefGoogle ScholarPubMed
Sauvant, D 1996. A comparative evaluation of models of lactating ruminant. Annales de Zootechnie 45, 215–235.Google Scholar
Sauvant, D, Morand-Fehr, P 1978. La capacité d’ingestion de la chèvre laitière. In Advances in goat production (ed. P Morand-Fehr, D Sauvant and M De Simiane), p. 42. Cycle Approfondi d’Alimentation Animale, INAPG, Paris.Google Scholar
Sauvant, D, Phocas, F 1992. A mechanistic model to simulate the long term regulation of the dairy cow nutrition. Journal of Dairy Science 75 (Suppl. 1), 168.Google Scholar
Sauvant, D, Giger-Reverdin, S, Meschy, F 2007. Alimentation des caprins. In Alimentation des bovins, ovins et caprins (ed. INRA), pp. 137–148. Editions Quae-INRA, Versailles, France.Google Scholar
Sorensen, JT, Kristensen, ES, Thysen, I 1992. A stochastic model simulating the dairy herd on a PC. Agricultural Systems 39, 177–200.CrossRefGoogle Scholar
Tess, MW, Kolstad, BW 2000. Simulation of a cow-calf production systems in a range environment: I. Model development. Journal of Animal Science 78, 1159–1169.CrossRefGoogle Scholar
Williams, JC 1993. Influence of farm, parity, season and litter size on the lactation curve parameters of white British dairy goats. Animal Production 57, 99–104.Google Scholar